• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.147-156
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• 1999

Skeletal Cl III malocclusion is an orthopedic appliance mainly used for growing children with maxillary undergrowth, which largely entails skeletal Cl III malocclusion. It improves anterior crossbite and maxillary position and thus, enables patients to attain favorable Profile but often involves unfavorable profile with protrusive upper and lower lips. Therefore, if orthodontists have knowledge of which condition helps obtain favorable occlusion and profile, they are able to predict the prognosis and limitation of the treatment. This study was done in order to help obtain favorable Profile after treating growing skeletal Cl III children. In the study, we classified childern into two groups, the one with favorable profile(Group 1, n=12) and the other with unfavorable profile(Group 2, n=14) and, with retrospective study using pre- and post-treatment lateral cephalogram, drew the following conclusions. 1. As patients had more serious labioversion of upper incisors, they were more unlikely to have favorable profiles after the treatment. Protrusion of prosthion, which was related with maxillary incisors, also affected profiles. 2. As the NL-ML angle before the treatment was small, it was more likely to get favorable profile. 3. As the degree of lower lip protrusion was high, it was likely to have bialveolar protrusion after the treatment. 4. As the degree of downward and backward rotation of mandible was high, it was likely to get unfavorable profile.

• The korean journal of orthodontics
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• v.32 no.6 s.95
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• pp.455-466
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• 2002

The objective of this study was to evaluate the changes that occurred over time in the distracted periodontal ligament space following the rapid retraction of a tooth by periodontal distraction after bone undermining surgery had been conducted in the dogs. The upper second premolars were extracted on the left and right side in 4 male beagle dogs. Immediately after extraction, the interseptal bone distal to the upper first premolar was thinned and undermined by grooving to decrease the bone resistance. Activating an individualized distraction appliance at the rate of 0.225mm twice a day, the upper first premolar was retracted rapidly toward the extraction socket. Periodontal distractions were performed for 5, 10, and 20 days, and 20-day-distraction cases were followed by maintenance periods of 0, 14, 28, and 56 days. After 20 days of rapid retraction, the average distal movement of the upper first premolar was 5.02mm, and the average mesial movement of the upper third premolars serving as an anchorage unit was 0.18 mm. On histological examination, the regeneration of bone occurred in a highly organized pattern. Distracted periodontal ligament space was filled with newly formed bone oriented in the direction of the distraction, and this was followed by extensive bone remodeling. This result was similar to those observed in other bones after distraction osteogenesis. In the periodontal ligament, the relationship between collagen fibers and cementum began to be restored 2 weeks after the distraction was completed, and showed almost normal features 8weeks after the completion of the periodontal distraction. However, on the alveolar side, the new bone formation was still in process and collagen fiber bundles and Sharpey's fibers were not present 8 weeks after the completion of the periodontal distraction. Reactions in the periodontal ligament of the anchorage tooth represented bone resorption on the compressed side and new bone deposition on the tension side as occurred in conventional orthodontic tooth movement. In conclusion, the results of this study showed that periodontal structures on the distracted side of the periodontal ligament were regenerated well histologically following rapid tooth movement.

• The korean journal of orthodontics
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• v.30 no.4 s.81
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• pp.387-398
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• 2000

This study was aimed to observe the effect of Anterior J hook headgear on the craniofacial structures in mixed dentition with Class II malocclusion. The laterial cephalograms of 20 children treated by Anterior J hook headgear were traced, digitized and statistically analyzed. The results were as follows : 1. Forward growth of maxilla was inhibited. 2. Rotational effect of maxilla was not observed. 3. There was distal movement of maxillary dentition. 4. Maxillarly_dentoalveolar growth changes were more effective in anterior portion than posterior portion. 5. Mandible maintained a normal growth and mandibular plane angle was maintained during treatment period. 6. The ratio of anterior facial height to posterior facial height was almostly not changed.

• The korean journal of orthodontics
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• v.31 no.2 s.85
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• pp.199-207
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• 2001

The segmented TMA T-loop spring, used for reciprocal space closure and described by Burstone, was used to achievebodily movement of canine. Photoelastic analysis is a technique for the transformation of internal stress into visible light patterns. The two-dimensional photoelastic stress analysis was performed, and stress distribution was recorded by photography. The purpose of this study was to visualize photoelastically the distribution of forces transmitted to the alveolus and surrounding structures using new segmented TMA T-loop spring for canine retraction. The results were as follows: 1. Decreased activation produced decreased stress of upper 1st. premolar extraction site and increased intrusive stress of upper 1st. molar, regardless of T-loop position. 2. At 5mm activation, More posterior positioning of T-loop Produced an increased stress in upper 1st. premolar extraction site. 3. At 3mm activation, More posterior positioning of T-loop produced an increased stress in upper 1st. premolar extraction site and mesial lower half of upper 1st. molar mesio-buccal root. 4. At 1mm activation, More anterior positioning of T-loop produced an increased stress in upper mesial and blew apex area of upper canine root. 5. 0.25 B/L ratio and 3mm activation produced bodily movement of canine. To summarize, desired tooth movement and anchorage requirement is possible by altering the activation and mesio-distal position of the T-loop spring.

• The korean journal of orthodontics
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• v.40 no.3
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• pp.195-206
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• 2010

The aim of this report is to present an intraoral upper molar distalization system supported with zygomatic anchorage plates (Zygoma-gear Appliance, ZGA). This system was used for a 16-year-old female patient with a Class II molar relationship requiring molar distalization. The system consisted of bilateral zygomatic anchorage plates, an inner-bow and heavy intraoral elastics. Distalization of the upper molars was achieved in 3 months and the treatment results were evaluated from lateral cephalometric radiographs. According to the results of the cephalometric analysis, the maxillary first molars showed a distalization of 4 mm, associated with a distal axial inclination of $4.5^{\circ}$. The results of this study show that an effective upper molar distalization without anchorage loss can be achieved in a short time using the ZGA. We suggest that this new system may be used in cases requiring molar distalization in place of extraoral appliances.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.506-512
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• 2007

Traumatic injury of tooth in children is commonly occurred problem. It is classified into tooth, periodontal tissue, supporting bone, soft tissue injury by it's area and extent. Among the periodontal tissue injuries, traumatically intruded teeth are common in anterior maxillary area, though the occurrence rate is rather low, the pulp and supporting tissue injury is possible by vertical impact. The treatment method of traumatically intruded teeth is various. Observation on the spontaneous reeruption for 3-4 weeks is recommended if the traumatized teeth are deciduous teeth or slightly intruded immature permanent anterior teeth. If this did not occur because the extent of intrusion is severe or the traumatized teeth are mature permanent anterior teeth, orthodontic traction is applied by fixed/removable appliances. At this time, light and continuous force is applied for the extrusive movement of the intruded teeth. When above procedures are impossible, surgical repositioning and fixation is recommended. In these cases, we performed conventional endodontic therapy for pulp necrosis and orthodontic traction with fixed appliance. We obtained satisfactory results and will report that.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.1
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• pp.121-130
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• 2023

In children, large odontogenic cysts affect adjacent anatomical structures as well as displace developing permanent teeth. Odontogenic cysts are treated via enucleation or marsupialization. This case reports a 5-year-old boy and a 10-year-old boy who have not only displaced 3 or more permanent teeth but also elevated the maxillary sinus floor due to the large size of the cyst in the maxillary anterior region. In both cases, marsupialization was selected to minimize complications. After marsupialization, a customized acrylic obturator, window opening, and orthodontic traction for eruption guidance were gradually attempted, and it showed a good prognosis, so we report these cases.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.4
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• pp.512-518
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• 2010

The impaction of the maxillary permanent incisor is a common clinical problem and is mostly found at the "labial to the alveolar process." Surgical exposure and orthodontic treatment with fixed orthodontic appliances can be considered if normal eruption of the labillay impacted tooth is not expected. Surgical exposure of the impacted tooth, that is usually under the attached gingiva or is surrounded by alveolar bone through gingivectomy and removal of alveolar bone, may give a rise to complications such as diminution in the width of the attached gingiva, inflammation of the gingiva, and the loss of marginal alveolar bone. Therefore, closed eruption technique, which includes surgical exposure and orthodontic treatment with fixed orthodontic appliances followed by repositioning of surgical flap, is preferred. However, apically repositioned flap of the impacted tooth, which is beneath the movable submucosal area or is above the alveolar crestal area, can prevent unwanted exposures and facilitate successful tooth eruption. In this report, we described esthetic results of three patients with unerupted maxillary permanent incisor who were performed with an apically positioned flap without the loss of attached gingiva.

• The korean journal of orthodontics
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• v.41 no.5
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• pp.324-336
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• 2011

Objective: The aim of this study was to conduct three-dimensional finite element analysis of individual tooth displacement and stress distribution when a posterior retraction force of 200 g was applied at different positions of the retraction hook on the transpalatal arch (TPA) of a molar, and over different lengths of the lever arm on the maxillary anterior teeth in lingual orthodontics. Methods: A three-dimensional finite element model, including the entire upper dentition, periodontal ligaments, and alveolar bones, was constructed on the basis of a sample (Nissan Dental Product, Kyoto, Japan) survey of Asian adults. Individual movement of the incisal edge and root apex was estimated along the x-, y-, and z-coordinates to analyze tooth displacement and von Mises stress distribution. Results: When the length of the lever arm was 15 mm and 20 mm, the incisal edge and root apex of the anterior teeth was displaced lingually, with a maximum lingual displacement at the lever arm length of 20 mm. When the posterior retraction hook was on the root apex, the molars showed distal displacement. When the length of the lever arm was 20 mm, anterior extrusion was reduced and the crown of the canine displaced toward the buccal side, in which case, the retraction hook was on the edge, rather than at the center, of the TPA. Conclusions: The results of the analysis showed that when 6 anterior teeth were retracted posteriorly, lateral displacement of the canine and lingual displacement of the incisal edge and root apex of the anterior teeth occur without the extrusion of the anterior segment when the length of the lever arm is longer, and the posterior retraction hook is in the midpalatal area.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.675-681
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• 2005

The Horseshoe appliance was introduced by Dr. Schwarz, and it is used to correct sagittal relationships by elastic force in class III malocclusion. It minimizes the increment of lower anterior facial height and allows the mandible to be repositioned harmoniously with the soft tissue and muscle matrix of the jaw It has the advantages of better patient cooperation, easier construction, and more effective modification. In the patients who were treated with Horseshoe appliance, forward growth of maxilla and counterclockwise rotation of occlusal plane with labioversion of maxillary incisors and linguoversion of mandibular incisors were obtained. Minimum downward and backward rotation of mandible was accepted, so increasing of lower anterior facial height was minimized.